As illustrated in U.S. Pat. Nos. 2,639,615; 2,997,879; 2,136,181; 1,484,815, and 1,481,986, barometric pressure has been displayed in the past through the utilization of a stylus adjacent a roll of paper, with the stylus providing an ink trace of the barometric pressure, or by the utilization of a thermosensitive paper and an appropriate stylus. Here there is relative movement between the stylus and the paper, with barometric readings recorded on a real-time basis without prior storage of the data.
One of the major problems with such displays is that they must be continuously reset and provided with either paper rolls, cylinders or the like; and/or provided with inking apparatus for the stylus utilized to record the barometric pressure.
Importantly, none of the prior barometers are capable of displaying continuous barometric information on a continuous first in, first out (FIFO) basis. Additionally, because these are real-time barometers with no stored data, there is no ability to alter the time span of data displayed on the chart; i.e. to "zoom" in on barometric information over a given time period. Moreover, as far as prior traces of barometric pressure, there is no separate indication on the display of a storm condition or, for instance, whether the barometric pressure is increasing or decreasing at the particular moment of measurement and display.
Moreover, there is no easy way to adjust such systems for the altitude of the barometer. For instance, should the display be a desk mounted display or wall mounted display, it is often times necessary to calibrate such devices by obtaining the barometric pressure at the location via a table or chart and then recalibrating the stylus to that point. This is both inconvenient and error prone.
On the other hand, were it possible merely to dial in the average altitude at the location or the city or town at which the barometer is located, then ease of calibration would be established. In the past, U.S. Pat. Nos. 1,485,152; 2,164,601; 2,609,691; 2,750,801; 2,953,024; 3,867,680, and 4,106,343 were devoted to calibration of altimeters which utilize barometric Pressure sensing means. However none of these calibration techniques are easily set and, in certain instances, require a sophisticated technician or mechanic. Also none are programmable.
Almost all pointer type barometers have a storm warning or indication on their dial. However, none apparently have an alarm or indicator which is actuated when a storm condition is present. In general, an impending storm or inclement weather is indicated if the barometric pressure drops below 29.92 inches at sea level, this indicates an impending storm. However the sensed barometric pressure must be adjusted for altitude if the device is to indicate with any accuracy the potential of an oncoming storm. Additionally, inclement weather is indicated when there is a pressure drop in excess of 0.05 inches per hour in barometric pressure, regardless of absolute pressure. Presently, no barometric pressure indicators for use in predicting weather utilize adjusted absolute barometric pressure thresholds to indicate storm conditions. Nor do they employ rate-of-change thresholds for storm indicating alarms. Note, U.S. Pat. Nos. 1,920,048; 2,853,393; 3,595,077, and 3,785,339 show systems which indicate inclement weather potential with or without an alarm function.
Note also, that clocks have been combined with barometers as illustrated in U.S. Pat. Nos. 2,510,402; 2,716,327; 3,157,985; 3,653,203, and 4,694,694. However, none of these patents describe a display with a continuously updated barometric pressure trace. Other U.S. Patents describing barometers and the display of atmospheric pressure are: U.S. Pat. Nos. 4,133,209; 4,010,646; 3,890,614; 3,852,711; 3,839,626; 3,829,640; 3,545,269; 3,333,565; 3,083,343; 3,079,799; 2,953,024; 2,703,932; 1,952,037; 1,848,053; 1,786,219; 1,534,306; 1,100,775, and 1,041,382.